Integrated circuits are widely used in many consumer, commercial and other applications. As is well known to those having skill in the art, an integrated circuit includes a large number of active devices, such as transistors, in an integrated circuit substrate, such as a semiconductor substrate. As is also well known to those having skill in the art, integrated circuit fabrication may include a large number of masking steps, which selectively expose regions of an integrated circuit substrate and/or layers thereon. Implantation of dopants and/or other species into the integrated circuit substrate and/or layers thereon may be provided through the exposed regions of the mask. For example, in fabricating integrated circuit field effect transistors, also referred to as insulated gate field effect transistors, MOSFETs or CMOS devices, it is known to selectively implant dopants into active regions of an integrated circuit substrate using various masks. Unfortunately, as the integration density and/or complexity of integrated circuit devices continues to increase, the number of masking steps may undesirably increase and/or it may be difficult to use conventional materials to form these devices.
In fabricating an integrated circuit transistor, it is known to use a first mask and first gate spacers to form source/drain extension regions, also referred to as extension regions or halo regions. It is also known to use a second mask, and second gate spacers, to form the source/drain regions.
In particular, referring to FIG. 1A, a first mask 100 may be used in implanting first dopants 110, to form extension regions 130 on opposite sides of an insulated gate 120, while masking other devices 140. Later, as shown in FIG. 1B, a second mask 150 may be used in connection with sidewall spacers 160, to implant source/drain dopants 180, and thereby form source/drain regions 170.